1. Field of the Invention
The present invention relates to cable glands and more particularly, to a cable gland assembly, which provides enhanced protection and multiple packing, airtight, waterproof, dustproof and anti-tensile effects.
2. Description of the Related Art
After installation of a cable in an electric box or any junction box of a machine, telecom or network system by means of a cable gland, the cable may be disconnected or loosened from the gland when stretched accidentally by an external force, causing leakage. To avoid this problem, many improved cable gland designs are created, such as U.S. Pat. No. 5,927,892 entitled “Device for fastening a cable to a board”, U.S. Pat. No. 8,490,513 entitled “Cable gland and gasket ring assembly”, U.S. Pat. No. 8,288,667 entitled “Double-packing cable and flexible conduit gland”. These prior art designs commonly comprise a mounting member, a clamping member, a packing ring and an outer cap. The mounting member is connected to a board member and screw-connected with the outer cap. The clamping member is sleeved onto the packing ring in the outer cap and compressed by the outer cap to wrap the packing ring about the periphery of the inserted cable, thereby locking the cable and protecting it against moisture and water.
However, the aforesaid prior art designs simply has one packing ring set between the mounting member and the outer cap to wrap about the inserted cable, i.e., these prior art designs simply provide one single packing effect that is insufficient to firmly hold down the cable. When the cable is stretched accidentally by an external force, a water leakage can occur.
According to the cable gland with water seal rings of U.S. Pat. No. 8,490,513 and the double-packing cable and flexible conduit gland of U.S. Pat. No. 8,288,667, the packing member comprises a first packing segment compressible to clamp on the inserted flexible conduit, and a second packing segment compressible to clamp on the inserted cable, achieving double-layer packing effects. However, because the first packing segment and the second packing segment are formed in one single packing member, the first packing segment and the second packing segment can be destructed to lose its packing functioning when the flexible conduit or cable is stretched by an external force. Actually, these designs simply provide one layer of packing effect.
Further, when a cable gland is selected for dynamic mechanical application, outdoor application, or application in a deep-water environment or high explosive atmosphere, it must have a very high IP (International Protection) rating. However, the IP ratings of the aforesaid prior art designs are insufficient for dynamic mechanical application, or application in a deep-water environment or high explosive atmosphere.
Therefore, it is desirable to provide a gasket ring for cable gland, which eliminates the aforesaid problems.